From Gerard Briscoe:
Application to spoof your Ethernet or Airport mac address. It will also generate a random address for you. Admin password required to change mac addresses. Choice of vendor for random generation. Just copy to your applications folder to install. Limitations -does not work with Mac Pro airport Released under GPL. The scripts used to get and set the mac address, for both the Airport and Ethernet interfaces, were modified from one written by Fouad Sethna. Request of user admin password is now handled more securely by the operating system, rather the program itself. This is in response to user feedback that it looked suspicious otherwise. Compatibility with Mac OS X 10.5 Leopard.
What's new in this version:
Upgraded the code base extensively, so that the information gathering is more resilient to system updates, which has previously proved problematic.